Ethnic and politically linked violence in Pakistan's financial capital Karachi has killed 800 people so far this year, the country's independent human rights organisation said Friday.

"About 800 people have been the victims of violent shootings in the last seven months," Zohra Yusuf, chairwoman of the Human Rights Commission of Pakistan (HRCP), told AFP.

Parts of the Arabian Sea port city have become battlegrounds in recent weeks with authorities unable to prevent violence, blamed on activists from political parties representing competing ethnic groups, from spiralling.

The HRCP previously said 490 people were killed in the first six months of the year and on Friday that another 300 people died in July.

"The figures compiled by our staff and the death toll for the last month confirmed by the police shows the number of victims of violence was not less than 300," Yusuf said.

The government has campaigned to end the clashes and deployed hundreds of additional police and paramilitary forces in the city, but the killings have continued with 58 people reported dead in five days alone this week.

Much of the violence has been blamed on tensions between supporters of the Muttahida Qaumi Movement (MQM), rooted in the Urdu-speaking majority, and the Awami National Party (ANP), which represents ethnic Pashtun migrants.

HCRP says the violence in Karachi is the deadliest since 1995, when more than 900 killings were reported in the first half of the year.